In my last post, I mentioned the usage of customized query_command to look
up contact email address. Some might wonder why I would want to do this despite
there are many mature tools, such as abook and lbdb, available.

The reason is simple. I just do not like to install extra any extra packages
for mutt contact management. Having a few scripts safely backed-up to github
and providing the same functionality, is much easier to maintain.